15:30 〜 16:30
[S01-P-12] Very wide observation range of the developed borehole stress meter and comparison with STS seismometer
We have developed a stress meter which can record continuous stress variation in a deep underground. The Tohoku earthquake (M9.0) occurred on 11 March 2011 in Pacific Ocean. The stress meters operated by Tono Research Institute of Earthquake Science (TRIES) could beautifully record whole wave forms caused by the earthquake. The stress meters can respond from DC frequency. However, almost all of STS seismometers in Japan scaled out and could not record larger amplitudes of the wave forms. It is important to record long period seismograms for especially earthquakes happened in sea for estimating occurrence of large Tsunami. Therefore, we compared observation ranges among STS seismometer, stress meter and strain meter. We also investigated how large amplitude variations can be observed by stress meter and strain meter and characteristics of the meters. The main results obtained are as follows:
1. Vertical component of the stress meter of TOS borehole station (depth: 512m) recorded maximum amplitude of about 300kPa for the 2011 Tohoku earthquake. However, the stress meter can record amplitude of about 5 MPa for even high sensitivity setting up.
2. Stress meter and strain meter for even high sensitivity setting up have as 10 times wider observation range than that of STS seismometers.
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3. The stress meter can observe not only stress but also strain. And observation range of strain meters are about 2x10^-4 , though maximum amplitudes of observed strain were about 5x10^-5.
4. The stress meter developed by us makes use of estimating Tsunami generation, determining magnitude and research of earthquake generation because it can record whole stress seismogram without scaling out even for gigantic earthquake.
1. Vertical component of the stress meter of TOS borehole station (depth: 512m) recorded maximum amplitude of about 300kPa for the 2011 Tohoku earthquake. However, the stress meter can record amplitude of about 5 MPa for even high sensitivity setting up.
2. Stress meter and strain meter for even high sensitivity setting up have as 10 times wider observation range than that of STS seismometers.
.
3. The stress meter can observe not only stress but also strain. And observation range of strain meters are about 2x10^-4 , though maximum amplitudes of observed strain were about 5x10^-5.
4. The stress meter developed by us makes use of estimating Tsunami generation, determining magnitude and research of earthquake generation because it can record whole stress seismogram without scaling out even for gigantic earthquake.